A national Space Exploration Initiative (SEI) program is presently being contemplated by NASA and is expected to be pursued. A study of SEI requirements has placed cryogenic in-space transfer technology high on its list of technology evolution priorities. Reusable chemical and nuclear space transportation vehicles (STV's) will use cryogenic liquid Hydrogen (LH2) and liquid Oxygen (LOX) propellants. Contemplated space depot concepts for servicing these vehicles use large mechanical pumps, special zero-gravity mass gauges, and require both depot and vehicle tanks to be constructed with several internal hoop-like capillary acquisition channels. The transfer process using this approach is necessarily slow by Earth standards. Time must be taken to ensure that liquid cohesion to acquisition channels is not broken. If there is gas in the transferring liquid (mixed phase), this can also halt the flow process, and/or cause false fill level readings. While ground launch facilities can fill and drain 20,400 kg. (45,00 lbs) of cryogens from today's Centaur space vehicle in times on the order of 1/2 to 11/2 hours, it could take two to three days for the capillary process. Further, this technology has not been proven in a zero gravity environment. Expensive experimentation to demonstrate and quantify its processes remains to be conducted. Because of this perceived development burden, the role of space propellant transfer and top off has been moved well into the future in current estimates.
Although many arrangements that have been proposed for such purposes are noteworthy to one extent or another, none appear to achieve the objectives of an efficient, reliable, practical, reasonably priced large cryogenic propellant depot for fueling and draining reusable STV's before and after missions.
None of the previously proposed arrangements provide the benefits attendant with the present invention. The present invention achieves its intended purposes, objects and advantages over the previous proposal through a new, useful and unobvious combination of component elements, with the use of a minimum number of functioning parts, at a reasonable cost to manufacture, and by employing only readily available materials.
It is a general object of this invention to provide a large propellant depot for fueling and draining STV's before and after missions and/or refueling artificial satellites to extend their useful life.
It is a further general object of the invention to provide a centrifugal propellant depot that works by a natural principle, requires no pumps for propellant transfer, and which will have no breakdowns due to pump or sensing equipment malfunction.
It is a specific object of this invention to provide a centrifugal pumping propellant depot that is efficient to operate, transfers propellant at an optimum rate, and is less expensive in both initial and life cycle costs than presently contemplated arrangements.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.